Table 1 Extraction of Inorganic P from Soils*
From: Phosphorus retention in calcareous soils and the effect of organic matter on its mobility
| Extractant | P forms extracted |
|---|---|
| NaOH/NaCl | Al- and Fe-bound |
| Na citrate-bicarbonate (CB) | Labile pedogenic Ca-rich |
| Na citrate (C) | Pedogenic Ca-phosphates |
| Na citrate-ascorbate (CA) | Occluded in poorly crystalline Fe-oxides |
| Na citrate-bicarbonate-dithionite (CBD) | Occluded in crystalline Fe-oxides |
| Na acetate | Ca phosphates (excl. lithogenic apatite) |
| HCl | Lithogenic apatite |